(1) Field of the Invention
The present invention generally relates to methods of reducing inflammation. More specifically, the invention relates to methods for reducing inflammation caused by proinflammatory cytokines or an inflammatory cytokine cascade.
(2) Description of the Related Art
Vertebrates achieve internal homeostasis during infection or injury by balancing the activities of proinflammatory and anti-inflammatory pathways. However, in many disease conditions, this internal homeostasis becomes out of balance. For example, endotoxin (lipopolysaccharide, LPS) produced by all Gram-negative bacteria activates macrophages to release cytokines that are potentially lethal (44; 10; 47; 31).
Inflammation and other deleterious conditions (such as septic shock caused by endotoxin exposure) are often induced by proinflammatory cytokines, such as tumor necrosis factor (TNF; also known as TNFxcex1 or cachectin), interleukin (IL)-1xcex1, IL-1xcex2, IL-6, IL-8, IL-18, interferonxcex3, platelet-activating factor (PAF), macrophage migration inhibitory factor (MIF), and other compounds (42). Certain other compounds, for example high mobility group protein 1 (HMG-1), are induced during various conditions such as sepsis and can also serve as proinflammatory cytokines (57). These proinflammatory cytokines are produced by several different cell types, most importantly immune cells (for example monocytes, macrophages and neutrophils), but also non-immune cells such as fibroblasts, osteoblasts, smooth muscle cells, epithelial cells, and neurons (56). Proinflammatory cytokines contribute to various disorders, notably sepsis, through their release during an inflammatory cytokine cascade.
Inflammatory cytokine cascades contribute to deleterious characteristics, including inflammation and apoptosis (32), of numerous disorders. Included are disorders characterized by both localized and systemic reactions, including, without limitation, diseases involving the gastrointestinal tract and associated tissues (such as appendicitis, peptic, gastric and duodenal ulcers, peritonitis, pancreatitis, ulcerative, pseudomembranous, acute and ischemic colitis, diverticulitis, epiglottitis, achalasia, cholangitis, coeliac disease, cholecystitis, hepatitis, Crohn""s disease, enteritis, and Whipple""s disease); systemic or local inflammatory diseases and conditions (such as asthma, allergy, anaphylactic shock, immune complex disease, organ ischemia, reperfusion injury, organ necrosis, hay fever, sepsis, septicemia, endotoxic shock, cachexia, hyperpyrexia, eosinophilic granuloma, granulomatosis, and sarcoidosis); diseases involving the urogential system and associated tissues (such as septic abortion, epididymitis, vaginitis, prostatitis and urethritis); diseases involving the respiratory system and associated tissues (such as bronchitis, emphysema, rhinitis, cystic fibrosis, adult respiratory distress syndrome, pneumonitis, pneumoultramicroscopicsilicovolcanoconiosis, alvealitis, bronchiolitis, pharyngitis, pleurisy, and sinusitis); diseases arising from infection by various viruses (such as influenza, respiratory syncytial virus, HIV, hepatitis B virus, hepatitis C virus and herpes), bacteria (such as disseminated bacteremia, Dengue fever), fungi (such as candidiasis) and protozoal and multicellular parasites (such as malaria, filariasis, amebiasis, and hydatid cysts); dermatological diseases and conditions of the skin (such as burns, dermatitis, dermatomyositis, sunburn, urticaria warts, and wheals); diseases involving the cardiovascular system and associated tissues (such as vasulitis, angiitis, endocarditis, arteritis, atherosclerosis, thrombophlebitis, pericarditis, myocarditis, myocardial ischemia, congestive heart failure, periarteritis nodosa, and rheumatic fever); diseases involving the central or peripheral nervous system and associated tissues (such as Alzheimer""s disease, meningitis, encephalitis, multiple sclerosis, cerebral infarction, cerebral embolism, Guillame-Barre syndrome, neuritis, neuralgia, spinal cord injury, paralysis, and uveitis); diseases of the bones, joints, muscles and connective tissues (such as the various arthritides and arthralgias, osteomyelitis, fasciitis, Paget""s disease, gout, periodontal disease, rheumatoid arthritis, and synovitis); other autoimmune and inflammatory disorders (such as myasthenia gravis, thryoiditis, systemic lupus erythematosus, Goodpasture""s syndrome, Behcets""s syndrome, allograft rejection, graft-versus-host disease, Type I diabetes, ankylosing spondylitis, Berger""s disease, Type I diabetes, ankylosing spondylitis, Berger""s disease, and Retier""s syndrome); as well as various cancers, tumors and proliferative disorders (such as Hodgkins disease); and, in any case the inflammatory or immune host response to any primary disease (13; 55; 30; 20; 33; 25; 18; 27; 48; 24; 7; 9; 4; 3; 12; 8; 19; 15; 23; 22; 49; 34).
Mammals respond to inflammation caused by inflammatory cytokine cascades in part though central nervous system regulation. This response has been characterized in detail with respect to systemic humoral response mechanisms during inflammatory responses to endotoxin (2; 54; 21; 28). In one set of responses, afferent vagus nerve fibers are activated by endotoxin or cytokines, stimulating the release of humoral anti-inflammatory responses through glucocorticoid hormone release (51; 41; 39). Previous work elucidated a role for vagus nerve signaling as a critical component in the afferent loop that modulates the adrenocorticotropin and fever responses to systemic endotoxemia and cytokinemia (14; 11; 52; 35). However, comparatively little is known about the role of efferent neural pathways that can modulate inflammation.
Efferent vagus nerve signaling has been implicated in facilitating lymphocyte release from thymus via a nicotinic acetylcholine receptor response (1). Clinical studies have also indicated that nicotine administration can be effective for treating some cases of inflammatory bowel disease (17; 36), and that proinflammatory cytokine levels are significantly decreased in the colonic mucosa of smokers with inflammatory bowel disease (40). However, none of these findings would suggest that cholinergic agonists can inhibit an inflammatory cytokine cascade, particularly those mediated by macrophages. Also, there is no suggestion in the literature that efferent vagus nerve stimulation is effective in inhibiting these cascades.
Accordingly, the inventor has succeeded in discovering that cholinergic agonists can inhibit the release of proinflammatory cytokines from a mammalian cell, either in vitro or in vivo. This inhibitory effect is useful for inhibiting inflammatory cytokine cascades that mediate many disease conditions. Furthermore, cholinergic agonist treatment in vivo can be effected to inhibit either local or systemic inflammatory cytokine cascades by stimulating efferent vagus nerves.
Thus, one embodiment of the present invention is directed to a method of inhibiting the release of a proinflammatory cytokine from a mammalian cell. The method comprises treating the cell with a cholinergic agonist in an amount sufficient to decrease the amount of the proinflammatory cytokine that is released from the cell. In preferred embodiments, the cell is a macrophage. Preferably, the proinflammatory cytokine is tumor necrosis factor (TNF), interleukin (IL)-1xcex2, IL-6, IL-18 or HMG-1, most preferably TNF. In preferred embodiments, the cholinergic agonist is acetylcholine, nicotine, muscarine, carbachol, galantamine, arecoline, cevimeline, or levamisole. In other preferred embodiments, the cell is in a patient suffering from, or at risk for, a condition mediated by an inflammatory cytokine cascade, preferably appendicitis, peptic, gastric or duodenal ulcers, peritonitis, pancreatitis, ulcerative, pseudomembranous, acute or ischemic colitis, diverticulitis, epiglottitis, achalasia, cholangitis, cholecystitis, hepatitis, Crohn""s disease, enteritis, Whipple""s disease, asthma, allergy, anaphylactic shock, immune complex disease, organ ischemia, reperfusion injury, organ necrosis, hay fever, sepsis, septicemia, endotoxic shock, cachexia, hyperpyrexia, eosinophilic granuloma, granulomatosis, sarcoidosis, septic abortion, epididymitis, vaginitis, prostatitis, urethritis, bronchitis, emphysema, rhinitis, cystic fibrosis, pneumonitis, pneumoultramicroscopicsilicovolcanoconiosis, alvealitis, bronchiolitis, pharyngitis, pleurisy, sinusitis, influenza, respiratory syncytial virus infection, herpes infection, HIV infection, hepatitis B virus infection, hepatitis C virus infection, disseminated bacteremia, Dengue fever, candidiasis, malaria, filariasis, amebiasis, hydatid cysts, burns, dermatitis, dermatomyositis, sunburn, urticaria, warts, wheals, vasulitis, angitis, endocarditis, arteritis, atherosclerosis, thrombophlebitis, pericarditis, myocarditis, myocardial ischemia, periarteritis nodosa, rheumatic fever, coeliac disease, congestive heart failure, adult respiratory distress syndrome, Alzheimer""s disease, meningitis, encephalitis, multiple sclerosis, cerebral infarction, cerebral embolism, Guillame-Barre syndrome, neuritis, neuralgia, spinal cord injury, paralysis, uveitis, arthritides, arthralgias, osteomyelitis, fasciitis, Paget""s disease, gout, periodontal disease, rheumatoid arthritis, synovitis, myasthenia gravis, thryoiditis, systemic lupus erythematosus, Goodpasture""s syndrome, Behcets""s syndrome, allograft rejection, graft-versus-host disease, Type I diabetes, ankylosing spondylitis, Berger""s disease, Type I diabetes, ankylosing spondylitis, Berger""s disease, Retier""s syndrome, or Hodgkins disease. In more preferred embodiments, the condition is appendicitis, peptic, gastric or duodenal ulcers, peritonitis, pancreatitis, ulcerative, pseudomembranous, acute or ischemic colitis, hepatitis, Crohn""s disease, asthma, allergy, anaphylactic shock, organ ischemia, reperfusion injury, organ necrosis, hay fever, sepsis, septicemia, endotoxic shock, cachexia, septic abortion, disseminated bacteremia, burns, Alzheimer""s disease, coeliac disease, congestive heart failure, adult respiratory distress syndrome, cerebral infarction, cerebral embolism, spinal cord injury, paralysis, allograft rejection or graft-versus-host disease. In the most preferred embodiments, the condition is endotoxic shock. In some embodiments, the cholinergic agonist treatment is effected by stimulating efferent vagus nerve activity sufficient to inhibit the inflammatory cytokine cascade. Preferably, the efferent vagus nerve activity is stimulated electrically. The efferent vagus nerve can be stimulated without stimulating the afferent vagus nerve. Vagus nerve ganglions or postganglionic neurons can also be stimulated. Additionally, peripheral tissues or organs that are served by the vagus nerve can also be stimulated directly.
The present invention is also directed to a method of inhibiting an inflammatory cytokine cascade in a patient. The method comprises treating the patient with a cholinergic agonist in an amount sufficient to inhibit the inflammatory cytokine cascade, wherein the patient is suffering from, or at risk for, a condition mediated by the inflammatory cytokine cascade. The cholinergic agonist is preferably acetylcholine, nicotine, muscarine, carbachol, galantamine, arecoline, cevimeline, or levamisole, and the condition is preferably appendicitis, peptic, gastric or duodenal ulcers, peritonitis, pancreatitis, ulcerative, pseudomembranous, acute or ischemic colitis, diverticulitis, epiglottitis, achalasia, cholangitis, cholecystitis, hepatitis, Crohn""s disease, enteritis, Whipple""s disease, asthma, allergy, anaphylactic shock, immune complex disease, organ ischemia, reperfusion injury, organ necrosis, hay fever, sepsis, septicemia, endotoxic shock, cachexia, hyperpyrexia, eosinophilic granuloma, granulomatosis, sarcoidosis, septic abortion, epididymitis, vaginitis, prostatitis, urethritis, bronchitis, emphysema, rhinitis, cystic fibrosis, pneumonitis, pneumoultramicroscopicsilicovolcanoconiosis, alvealitis, bronchiolitis, pharyngitis, pleurisy, sinusitis, influenza, respiratory syncytial virus infection, herpes infection, HIV infection, hepatitis B virus infection, hepatitis C virus infection, disseminated bacteremia, Dengue fever, candidiasis, malaria, filariasis, amebiasis, hydatid cysts, burns, dermatitis, dermatomyositis, sunburn, urticaria, warts, wheals, vasulitis, angiitis, endocarditis, arteritis, atherosclerosis, thrombophlebitis, pericarditis, myocarditis, myocardial ischemia, periarteritis nodosa, rheumatic fever, Alzheimer""s disease, coeliac disease, congestive heart failure, adult respiratory distress syndrome, meningitis, encephalitis, multiple sclerosis, cerebral infarction, cerebral embolism, Guillame-Barre syndrome, neuritis, neuralgia, spinal cord injury, paralysis, uveitis, arthritides, arthralgias, osteomyelitis, fasciitis, Paget""s disease, gout, periodontal disease, rheumatoid arthritis, synovitis, myasthenia gravis, thryoiditis, systemic lupus erythematosus, Goodpasture""s syndrome, Behcets""s syndrome, allograft rejection, graft-versus-host disease, Type I diabetes, ankylosing spondylitis, Berger""s disease, Type I diabetes, ankylosing spondylitis, Berger""s disease, Retier""s syndrome, or Hodgkins disease. In more preferred embodiments, the condition is appendicitis, peptic, gastric or duodenal ulcers, peritonitis, pancreatitis, ulcerative, pseudomembranous, acute or ischemic colitis, hepatitis, Crohn""s disease, asthma, allergy, anaphylactic shock, organ ischemia, reperfusion injury, organ necrosis, hay fever, sepsis, septicemia, endotoxic shock, cachexia, septic abortion, disseminated bacteremia, burns, Alzheimer""s disease, coeliac disease, congestive heart failure, adult respiratory distress syndrome, cerebral infarction, cerebral embolism, spinal cord injury, paralysis, allograft rejection or graft-versus-host disease. In the most preferred embodiments, the condition is endotoxic shock. The cholinergic agonist treatment can be effected by stimulating efferent vagus nerve activity, preferably electrically.
In additional embodiments, the present invention is directed to a method for treating a patient suffering from, or at risk for, a condition mediated by an inflammatory cytokine cascade. The method comprises stimulating efferent vagus nerve activity of the patient sufficient to inhibit the inflammatory cytokine cascade. Preferred methods of stimulation and preferred conditions are as with the previously described methods.
In still other embodiments, the present invention is directed to a method for attenuation of a systemic inflammatory response to endotoxin in a patient. The method comprises stimulating efferent vagus nerve activity of the patient sufficient to inhibit an inflammatory cytokine cascade.
The present invention is additionally directed to a method for determining whether a compound is a cholinergic agonist. The method comprises determining whether the compound inhibits the release of a proinflammatory cytokine from a mammalian cell. In preferred embodiments the cell is a macrophage and the proinflammatory cytokine is TNF.